


Dancing with the Demon

by eternalparadox (paradoxicallysimplistic)



Series: Demonology, Magic, and SF... [2]
Category: Shingeki no Kyojin | Attack on Titan
Genre: Alternate Universe - Canon Divergence, Anal Sex, Bottom Levi (Shingeki no Kyojin), Demon Deals, Demons, Fantasy, M/M, One Shot, Top Eren Yeager, demon!Eren - Freeform
Language: English
Status: Completed
Published: 2018-03-30
Updated: 2018-03-30
Packaged: 2019-04-15 03:49:55
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,835
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14151294
Author URL: https://archiveofourown.org/users/paradoxicallysimplistic/pseuds/eternalparadox
Summary: Levi, Captain of the Scouting Legion, is hailed as Humanity's Strongest. His strength and abilities in battle are legendary.But he has a secret. One that he's held for over ten years... And the source of his abilities.





	Dancing with the Demon

**Author's Note:**

> Aloha guys. Kind of fallen out of a normal update schedule, and it'll be a while before I get around to posting regularly, but I'm still kicking. Was reminded that today was 3/30 - Eren's birthday - so I figured that I would wallow for a bit and finish off this one-shot. Enjoy!

“Captain!”

Levi didn’t bother responding, already on his way to eliminate the aberrant titan who refused to go down. It avoided the uncoordinated efforts of the newer cadets with ease, rushing off like a battering ram and crushing trees with ease. Levi knew it was too early to bring them on the mission, but with their dwindling numbers and Erwin’s push to reclaim the outer wall, they were the only ones available.

Many who lived behind those cushy walls, arguing against the purpose of the Survey Corps and the purportedly senseless deaths each mission were blissfully ignorant of the dangers and risks. They had never experienced the fear of man-eating monsters with exceptional regenerative ability, speed, and strength. And that obliviousness was often fatal. All too often, new recruits froze or shit themselves the first time they encountered a titan. It was one of the main causes of death – not that any following mission was any less dangerous. At least none of them had broken ranks and fled from battle this time.

Firing his gear at a nearby tree, Levi launched himself back in the air, swing around and making a wide detour around the side of the aberrant while it was still occupied and changing after the newer recruits. It was only about eleven-meters or so in height, but its thick burly arms and small head, made it difficult to strike at its vulnerable nape. As with all titans, its face was distorted, mouth and eyes much larger than normal, seeming to grin with each movement it made. Like a child, it chased after the closest humans, clumsily reaching out with its hands in a futile effort to grab them like flies in the air.

Keeping a wary eye on the aberrant’s movements, Levi took the opportunity as it was making a mad dash, lumbering after a speck of green, to make his attack. Blades out, he propelled himself towards the titan’s weak point, never stopping as he cut through the fleshy texture and straight through it. A familiar sizzle of heat crawled up his skin as the titan disintegrated into nothingness.

Breathing heavily, he looked up to examine the situation. After that last kill, the roars had died down. The area appeared to be clear, but one could never be too sure in these woods with titans skulking about.

“Oi, any more of those shits?” He asked one of the newer recruits, some kid with cropped hair and seemed vaguely in control of himself unlike the others whose eyes were glazed over in shock.

“Umm, no…” The recruit made a double take when he realized who he was addressing. “No, Captain Levi, sir! The aberrant was the last of them.”

“Tch, it better be.” Their gas tanks were running dangerously low, and Levi’s stamina was drained from fending off the surprise attack. “Find the others and give me a status update.”

 

Everyone knew to keep a wide berth away from the glaring Captain, not uttering a sound as he vanished into the woods.

Silvery beams shone down on Levi as he found himself in the middle of a small clearing in the forest. The peaceful silence at odds with the battle that had only taken. The signs of battle were everywhere. Crushed grasses and bushes, broken branches, and fallen trees, their trunks snapped in half like matchsticks. They had been toppled just as easily as a human would have been.

Five recruits had died in the last battle. They had been woefully unprepared. It was supposed to be a simple reconnaissance mission – the previous squad had mentioned no titans in the woods – but it had turned out to be a deathtrap. Each death weighted heavily on Levi’s conscience. If he had been a little faster, they’d still be alive. Levi had seen his share of deaths on the battlefield, but the cycle just kept repeating with no end in sight.

“Fuck.” He swore to himself, frustrated at his inability to kill the aberrant quicker. The entire fiasco could have been avoided… if only.

“Come out, brat.” Levi called out, knowing that _he_ was listening.

The wind picked up, and a moment later, a human emerged from the shadows of one of the trees. Except he wasn’t fully human. The golden glow of his eyes gave away its true identity as something not entirely human.

A demon, unable to be killed by mortal weapons. One that masqueraded as a human for fun, blending seamlessly into their lives, and formed contracts with whom he pleased. A stubborn, whimsical being with the ability to change lives.

And the same demon that Levi had contracted.

Eren. Or ‘Eren Jaeger’ as he called himself when pretending to be a human.

The bane of Levi’s existence. As well as his salvation.

Their meeting in the Underground more than ten years ago had been sheer coincidence. Eren had been drawn by the scent of violence, where he had discovered Levi starved and beaten up, nearly dead, after one of Kenny’s so-called training sessions. For whatever reason, the demon had taken fancy with him and they had formed a contract that day.

“You could always take me up on my offer and become one of us.” Eren sauntered up to him, eyes like molten gold, and a thoughtful expression on his face. “All you’d need is my blood.”

“Tch, no.”

“Why not?” Eren cocked his head in confusion. “You’d be immortal and have all the strength and speed to eliminate titans. None of this constant sneaking away. Not that it hasn’t been immensely enjoyable.” There was a salacious smirk as Eren licked his lips.

“I’ll think about it.” Levi grunted, folding his cloak and placing it on a rock nearby. Just because he was meeting for a nighttime rendezvous didn’t mean his clothes needed to get mussed up.

Over the years, the thought of gaining the same powers as the demon had become more and more tempting. Of course, according to what Eren had told him, those powers would be a side effect of their bonding. It wouldn’t be much difference from his current situation, except Levi would no longer be human. He would be _mated_ to a demon. And that changed everything.

“You humans are weird. I don’t get it.”

Ignoring Eren’s musings, Levi untied his cravat and unbuttoned his shirt. There was one reason, and only one reason he would have left camp to meet up with the demon.

Sex.

On the verge of death and willing to do anything to survive, he had agreed to the terms Eren had laid out, not fully understanding what they entailed. The contract itself gave him a small boost in strength, speed, and stamina. Enough to win a couple of fist fights and brawls, but nothing too spectacular. It was only during Levi’s teenaged years, desperate to stay alive, that Eren had explained the full details of the contract. Namely, absorption of the demon’s vitality was key, and the easiest way was contact with his bodily fluids.

It all depended on the method of exposure, length of exposure, and the source. Blood was most potent, followed by semen, sweat, and then saliva.  While ingestion was easiest, any ill-gotten abilities would wear off over a matter of hours as his body broke it down. In contrast, absorption through constant skin contact was messy, but lasted longer. Of course, no matter how or what Levi did, it was largely driven by whatever sexual inclinations the demon had.

At first he had opted to abstain from the stipulations in their contract, refusing to exchange his body for such ill-gotten abilities. But his resistance had cost his best friends their lives. Since then, he had made sure to keep regular contact with Eren – the demon had even followed him and joined the Survey Corps for ‘fun’ – to ensure he was always in good fighting shape. There were too many unknown variables in their expedition to rid all titans, and Levi needed to be in top fighting condition. But his earlier failure proved that their current arrangement wasn’t sufficient.

Folding his smallclothes and laying them down, Levi turned to face Eren, who was openly appraising his naked form.

“Do you still have it?”

“Hmm?”

“The… plug.” The words were wrenched from his mouth.

“Of course I do.” The demon grinned slyly, pushing himself off the tree trunk he was lounging against. “Finally willing to use it?”

“…yes.”

“Fuck…” Eren groaned, voice shuddering with need. “I can’t wait to see you plugged up with my cum.” The demon had proposed it several times when the potency of ingesting blood or semen hadn’t lasted long enough. Levi had never experienced it before, unwilling to keep something up his ass longer than necessary, and in him throughout the day. But he would have to now. He shuddered at the idea, but it was the only way aside from turning into a demon.

“Tch, just get on with it.”

“Denial will only make it that much harder, kitten.” Heated breath brushed over Levi’s body, caressing and dispelling the chill from the cool evening air. “Turn around and put your hands against the tree.”

“Fuck you.” Despite his dislike of that shitty name, Levi turned around to face the tree. He had learned long ago that opposing Eren would only lead to his prolonged suffering at the hands of the demon. But that didn’t stop Levi from fighting the more powerful being.

“Oh, you can count on it.” Eren’s tongue found his ear and he shuddered at the contact. Hands came in contact with his ass, squeezing appreciatively. “I wonder how many people would react when they found out the _real_ reason why their precious Captain wears a cravat.” Teeth scraped against his pulse, fingers rubbing against his ass. “Or how you became _Humanity’s Strongest_ in the first place.”

“Shut up, brat.” Levi shot back with considerably less venom than usual, his arms and legs supporting him as best as possible under the circumstances.

“Feisty, aren’t you, kitten?” He barely managed to repress the loud moan when Eren rammed his fingers inside, directly hitting his prostate. The demon’s fingers were wetted with something, finding its way into his body with ease.  “Can’t have anyone else finding about your dirty little secret now, can we?”

Before Levi could do anything, a fistful of starched fabric – his cravat – was forced into his mouth. Groaning, Levi tried to expel the balled-up cloth out of his mouth, demanding Eren choose something else, but it was cleverly done and required more dexterity than he had at the moment.

Raising a hand to remove the damned gag, one of Eren’s hands grabbed his wrist and forced it back against the tree. “Did I say you could move, kitten?”

Levi would have spat it out and raged at the shitty demon, but that would only turn Eren on. The demon found preserve pleasure in making him submit, and his body gave it willingly.

Eren’s digits scissored inside him, stretching him with deliberate motions. For a creature born out of nightmare, Eren was always considerate never to cause too much pain or discomfort until the actual fucking began, taking his sweet time to inflict exquisite torture. And each and every time, Levi found his body melting a little more, needing the demon to hurry up. He had been reluctant at first, but it had quickly evolved into something different. Levi would never admit it, but it was becoming impossible to ignore the growing heat whenever Eren was nearby; his body constantly lusting to be dominated and filled up.

The fingers were eventually pulled out; the cravat effectively preventing the whimper of protest that would have slipped out.  Levi stiffened as something hard and hot replaced it, prodding against his entrance. Despite the number of times they had done it, he couldn’t help the shiver of trepidation each time.

Forcing his body to relax and accept the intrusion. The moment he did, Levi found himself shaking, his limbs turning to jelly, as Eren pushed himself completely in. The searing heat melting away any potential for pain.

“Such a pity I won’t be able to hear the sweet sounds you make as you’re fucked.” Eren muttered close to Levi’s ears, his hands plucking at Levi’s nipples, caging him between the demon and the tree. Sharp nails clawed lightly at his skin, leaving a trail of pink behind. Despite the evening air, Levi wasn’t cold at all. He was warm, inside and out. Eren rocked against him, nudging deeper inside, the wide girth tickling the edges of his sweet spot. Not enough to send him over the edge, but enough to drive him mad.

The slow rocking was quickly replaced with deliberate thrusts, the first couple slow, but growing fiercer with each passing second. Each movement was jarring, hitting his prostate spot on, and made Levi’s vision explode in color. It took everything Levi had to keep standing, his muscles weak from the onslaught. Eren’s tight grip moved his hips for him, forcing them back just as Eren rammed inside, the combined force making muffled moans escape despite the ball of fabric.

Eren was relentless, driving inside him and stoking the growing pressure. All too soon, Levi felt the familiar spasms signaling his release was near, his ass clenching around Eren’s shaft. But the demon knew it as well as a hand wrapped around his dick, stopping him from finding his release.

“Coming so soon, Levi?” He shook his head, trying to move against the iron-grip the demon had, but it was futile. “I didn’t think so. What’d we say before?” Eren pulled all the way, stalling for a brief moment, before slamming all the way in. Levi’s limbs were complete mush as Eren repeated the action. “You only get to cum when I say you do, kitten.”

Tears sprung out from the corners of his eyes as Eren continued his tortuous pace, the grip around his dick preventing him from finding release. The pace picked up quickly, though, each thrust more forceful than the last as Eren moved.

Levi thought he was going to pass out from the heady pleasure when Eren suddenly released his grip, hips slamming inside once more before stuttering and flooding him with liquid heat. It was too much and Levi felt himself coming, his body overly sensitized and trembling as he came, clutching around Eren’s dick.

Breathing heavily, he felt Eren pull out with an audible squelch. Before he could respond something else took his place, his ass immediately contracting around the cool glass tip that prodded at his entrance.

“There, nice and tight.” It slipped in easily, the smooth surface sliding in with little resistance, acting to counter the warmth inside him. Levi hadn’t even moved, but he could feel the edges stretching him out. Tomorrow was going to be hell on Earth.

“How do you like it, pet?” Levi moaned into the fabric as Eren tugged on the plug, pulling it in and out of his overly sensitized insides. The demon’s seed only made the movements easier as it slid in and out of him, the wide edge catching on his rim each time Eren pulled it out.

“Look how pretty you are. Such a naughty little boy.” Warm palms boldly massaged his ass, spreading his cheeks and bring them together again. His body easily soaking up the warmth from Eren’s body. “Wonder what the rest of them would say when they learn how much their previous Captain Levi loves being filled up.”

Having enough of the teasing, Levi swatted at the demon who acquiesced and backed away, smirking.

Forcing his body to cooperate, Levi wrenched the damned cravat out of his mouth, glaring at Eren who had taken up observing him, lazily leaning against a tree. The unearthly golds stared hungrily, ready to pounce at a moment’s notice. Levi wanted to swear and tell Eren off, but he couldn’t. Instead, his body kept thinking about how good it would be if the demon removed the goddamn object and fucked him again and again until he lost consciousness.

Choosing to ignore his traitorous body, Levi strode over to his clothing, flinching with every movement as the flared end stimulated his sensitive insides. His jaws ached from being held wide open for so long and he could feel the bruises forming against his skin. Leaning down to pick up his shirt, he bit the inside of his mouth, at each jolt of pleasure that through him as he moved, stiffly forcing his legs into his pants once more.

By the time he had buttoned up his shirt, his legs were ready to give away. His ass fluttering around the plug, the glass object teasing his insides with every movement. There was no way Levi was going to be able withstand the anymore stimulation. Walking was difficult enough, but there were also the damned horses to contend with.

If Levi wasn’t already in hell, he was now.


End file.
